FAA regulations mandate that a pilot, at set altitudes while descending to land, must have sufficient visibility to first see the airport, and then the runway. If at the predetermined altitudes the pilot is unable to either see the airport or the runway he is required to abort landing. When about one thousand feet from the runway, about one hundred feet up, and while travelling at about one hundred and eighty mph the pilot has about seven seconds to commit to landing.
On January 26'th of this year eleven people were killed and 89 injured on American Airlines flight 1420. About 5 minutes before touchdown Captain Richard Buschman said he hated droning around without having some clue where he was. Heavy rain had reduced visibility to less than a mile. Captain Richard Buschman exclaimed "Were off course" when the plane was several hundred feet from the runway--moments before he died. The plane touched down with its main landing gear to the right of the runway and its nose pointing to the left.
The FAA also mandates that a pilot have at least 600 feet of runway centerline clearly visible prior to and during take-off. In snow, fog, or heavy rain this is not possible. Although airborne conditions may be fine, runway visibility may keep planes grounded, or airborne when they want to land. Improving runway visibility in adverse weather could save millions of dollars a day at busy airports. It would also reduce delays, improve flight reliability, and enhance customer relations.
Rerouting due to poor visibility due to adverse weather is a particularly acute problem when airports are operating near full capacity. Delays are compounded.
Visibility is even more critical in the military. When landing on an aircraft carrier, the runway is short and narrow. The pilots must precisely position their plane and snag a rope to decelerate rapidly. Visibility is frequently poor. And there is no other place to land. Visibility is also sometimes a problem at NASA. If Cape Canaveral is overcast shuttles must continue in orbit, or alternatively, land in California and be air transported back to Cape Canaveral.
A better method of illuminating airports and runways is needed. The system of illumination which is needed must be able to penetrate rain, fog, and snow, so that visibility is extended in adverse weather conditions.